Paint and varnish remover containing ketone condensation solvents



Oct. 25, 1932. B. N. LOUGOVOY 1,884,765 PAINT AND VAfiNISH REMOVER CONTAINING KETONE CONDENSATION SOLVENTS Filed May 26, 1928 Z Sheets-Sheet l a a 7 Cum/5 1f Oct. 25, 1 3 B. N. LOUGOVOY 1,334,765

PAINT AND VARNISH REMOVER CONTAINING KETONE CQNDENSATION SOLVENTS Filed May 26, 19 2 Sheets-Sheet 2 CURVES I 5 g am (WM 2 4 6 8 l0 l2 l4 /6 I6 20 22 24 Patented Oct. 25 1932 UNITED STATES PATENT; OFFICE BORIS N. LOUGOVOY, MONTCLAIR, NEW JERSEY, ASSIGNOR 'IO CHADELOID CHEMICAL COMPANY, OF NEW YORK, N. Y., A.

PAINT AND VARNISH REMOVEE CONTAINING- KETONE CONDENSATION SOLVENTS Application mean 26,

This invention relates to a finish remover comprising ketonic condensation solvents and has for its object the production of a composition adapted for the removal of the finish from painted or varnished surfaces, or broadly from surfaces carrying a dried finish coating which it is desired to remove.

A useful paint and varnish remover already known is made with benzol and acetone in suitable proportions, carrying three or four ounces of paraffin wax per gallon.

The activity of a paint and varnish remover is usually tested in the trade by a method which is not absolutely scientific but nevertheless is regarded sufiiciently convincing to the user. This method involves the application of some of the removing composition to a surface coated with a paint or varnish and noting the time taken for the surface to wrinkle. The time necessary for producing this wrinkling effect is regarded as inversely proportional to the solvent action or cutting power of the removing composit-ion.

While this might be sufficient for ordinary testing by the customer, a more exact method of determination of comparative cutting power would be desirable in rating the removing action of various solvents.

The method adopted when working on the present problem was as follows: A piece of old painted wood was selected, taking care that the portion used had a good even, thick coat of paint, and this was cut into strips. Various solvents were placed in a series of test tubes and a strip of the painted wood was put into each test tube. The time which elapsed before the first appearance of any wrinkling was noted accurately for each sol- .vent by means of a stop watch. The comparative removing action was thus roughly represented by the number of seconds.

Solvent mixtures vary greatly in cutting power. In removers involving the use of a penetrating hydrocarbon, such as benzol, and

' a loosening solvent of an alcoholic or ketonic nature, a very great variation isobservable in the cutting action depending upon the choice of solvents. Practically speaking, benzol is the most active and cheapest penetrating hydrocarbon. Acetone is a readily available and highly effective ketone body which is being used in paint and varnish removers at the present time. e

In the course of my work along the line of CORPORATION OF WEST VIRGINIA 1928. Serial No. 280,955.

paint and varnish remover, I discovered that a product could be readily" obtained from acetone by treatment with a small amount of alkali which would produce a substantial increase in cutting power of a remover as compared with acetone-containing removers otherwise of a similar character.

In an effort to secure the quickest possible action for a paint and varnish remover, I proceeded first with the investigation of the cutting power of various single solvents of different natures, turning then to a mixture of two solvents, three solvents, etc. In this investigation many interesting features have been observed which are illustrated in the table below, the tests being conducted on painted strips as described above:

Table I Cutting Single solvents p0werseconds Bonzol 3, 600 Chlorobenzol 400 Anhydrous methyl aicoh 240 Anhydrous ethyl alcohol. 1, 020 Isopropyl alcohol (98%) 2, 400 Diacetone alcoh l 408 Acetone 80 Lugosol (The meaning or this will be explained in a later paragraph) 45 Methyl ethyl lmtone 75 Mesityl 'mrlrie 210 Fnrfural 300 Ethyl acetate 105 Binary mixtures (In equal parts) Benzol-anhydrous methyl alcohol Benzol-anhydrous ethyl alcohol... Benzol-nr-arnna Benzol-lugosol Benzol-methyl ethyl kotone.. Benzol-iurluraL- Benzol-ethyl acetate Ternary mixtures (In equal giurts) Benzol-anhydrous methyl alcohol-momma.-.

Bonzol-anhydrous methyl alcohol-lugosol Benzol-euhydrous methyl alcohol-methyl ethyl ketonc. Benzol-acetone-ethyl alcohol Bonzollugosol-mothyl acetate Petroleum naphtha En-ethyl alcohol-acetone- Petroleum naphtha :c)-ethyl alcohol-lugosol (2) Fraction boiling between C. and 80 0., obtained from commercial petroleum naphtha.

As stated at the beginning of this specification the main feature of the present invention is the use of a product which is obtained from acetone. This product represents a mixture of various ketone condensation products and should be regarded as ketone-condensationsolvent.

Acetone when subjected to the action of certain of the alkali metal hydroxides will undergo intermolecular condensation to form a number of products of higher molecular weight among which mesityl oxide, diacetone alcohol, phoron and iso-phoron are known.

I shall now describe in a general way the 7 preparation of the product which is the subj ect of the present specification.

To prepare this product, commercial acctone, preferably in pure form, is treated with an alkaline substance capable of causing condensation, forming a certain proportion of products of higher boiling point. Alkaline condensation agents are, for example, quick lime, calcium hydroxide, barium hydroxide and similar alkali metal hydroxides, and the like, insoluble in the acetone; or sodium or potassium hydroxides. The last two hy droxides are preferably used in minute amounts and preferably in such proportions as will dissolve completely'in the acetone. The acetone when exposed to a condensation agent of this character, or mixtures of such condensation agents, is permitted to undergo reaction and condensation, preferably at about room temperature for a period suflicient to bring about a substantial equilibrium between the higher boiling form and the acetone. The acetone mixture is then preferably neutralized and subjected to distillation. This may be carried out at ordinary pressure or in a vacuum. It is desirable to avoid acid reaction during distillation and therefore a condition of neutrality approximating the iso-electric point preferably is secured prior to said neutralization step. Various organic and inorganic acids may be used for the neutralization and the employment of gases containing carbon dioxide to form the carbonate or bicarbonate also are not precluded.

' Inthis connection it should be pointed out that with respect to the use of the above product in the present invention it is desirable to avoid the presence of any inorganic material which would remain in solution because any substances which are present in the solvents used for paint and varnish remover usually tend to decrease the cutting power of the solvent. For this reason when neutralizin gthe alkali-treated acetone it is advisable to use certain acids which form salts insoluble in acetone and in mixtures of acetone and other solvents used in paint and varnish removers. Tartaric acid was found one of the most satisfactory for the purpose. L

The material at this stage contains a series of condensation products of acetone, and a large amount of unaltered acetone. The use of this material (after careful neutralization) as such (i. e. without distilling oil the unconverted acetone), forms the subject matter of my copending case Ser. No. 289,328 filed June 29, 1928, and is not claimed in the present application. This material is termed, by me, activated acetone.

After suflicient time for the reaction has elapsed, the alkali-treated acetone is neutralized with a suitable acid and then is usually subjected to a fractional distillation. According to the intended use of the product distillation may be carried on in two ways.

1. Separating unconverted acetone and collecting the products which boil above (30 0. Such a product will contain a mixture of various condensation products and a small amount of acetone and will have a boiling 'ange from (50 C. up to about 170 C. This product 1 term crude lugo'sol. Such product is hereinafter, for convenience, termed lugosol, whether further purified or not.

2. After removing the unconverted acetone fraction the remaining product is fractionated into various fractions having a narrower boiling range.

In connection with the above described method of preparation of ketone condensation solvents (crude lugosol), it should be pointed outthat acetone may occur both as normal or ketonic acetone and also as isoacetone or enolie acetone. Enolic acetone has a structure (an-responding to that of unsaturated alcohol (hydroxy propylene). Normal or ketonic acetone presumably exists in equilibrium with iso or enolie acetone. Enolization apparently plays an important part in the condensation of acetone to form the higher boiling acetone derivatives. My work has shown that when acetone is treated with a small amount of alkali, such as potassium hydroxide to form a higher boiling derivative thereof, that under most advantageous conditions about Ath of its volume of diacetone alcohol will be formed with simultaneous formation of about oneeighth of its volume of product boiling between (l() C. and 150 C. In one treatment of alkali an equilibrium is reached in which more than about one-fourth of acetone will undergo condensation with about threefourths remaining unreacted. I have found thatthis unreacted acetone, when recovered from one alkali treatment or distillation and when again subjected to the same alkali treatment, is much less reactive than the fresh previously untreated acetone. This I find to be largely due to a lower enolie content and 'it therefore appears that enolie acetone and not ketonic acetone is the actual substance which will combine with itself (condensation reaction to form such higher boiling derivatives as diacetone alcohol,

etc.). This is also substantiated by the relative dilfcrences in the reactivity of commercial acetone derived from various sources.

I have found that certain substances may be added to acetone-alkali reaction mixtures hyde, are especially suitable as promoters.

By the use of such promoters the yield of crude lugosol can be increased to 44% by weight of acetone taken.

The crude lugosol used in the greatest part of examples given in the present specification was made from a commercial grade of acetone by treatment with small amount (03%) of potassium hydroxide, neutraliz ing the product of reaction with tartaric acid and distilling offthe unconverted acetone. The crude lugosol so obtained after stand ing in laboratory for a period of several months had the following boiling range:

Temperature range Per cent (30 to 70 C 14 70 to 80 C. 26 80 to 100C 32 125 to 140 C .8 140 to 170 C 20 The above figures should be regarded only as an illustration of material which may be used in the present invention and in no way am I restricting myself thereto. In practice the distillation range may vary according to the acetone originally usedand other physical conditions of reaction.

Referring to the preceding table (Table 1) representing the cutting power of various solvents, it should be noted that crude lugosol as compared with other ketone solvents, such as acetone, methyl ethyl ketone, mesityl oxide, and diacetone alcohol, has the quickest action.

The same observation is true for various mixtures of acetone with other solvents,both hydrocarbons (benzol or petroleum naphtha) and non-benzenoid solvents.

Comparing the cutting action of crude lugosol with the action of other active solvents, it should be noted the lugosol is the most effective. i

From the same table it should also be noted that while crude lugosol may contain mesityl oxide and diacetone alcohol, it is apparently not the presence of either one of. these two substances which produces the effect of a higher efiiciency because a mixture of acetone with diacetone alcohol and acetone with mesityl oxide gave a cutting rate much slower than the rate for crude lugosol itself. Therefore I it seems that the activity of crude lugosol should be credited to a special combination of various acetone condensation products formed simultaneously in the course of reaction.

WVhile the preferred form of ketone solvent for use in the present invention is crude lugosol, i. e., a product which is substantially free fromunconverted acetone, it is also possible to employ to advantage the raw product without distillation obtained by treating acetone with alkali substances as described above. This product was found not as effective or as active as crude lugosol but still had a greater cutting power than the acetone originally used for the preparation of said raw product. This may be seen from the table below which gives the cutting power in seconds as measuredon the same kind of wooden strips and by the same method as previously described:

Table II Treated Treated Treated acetone acetone acetone Solvent mixtures Sump X Samp- 2 samp- 3 Lugo- Acesol tone Alk. Neu. Alk. Non. Alk. Neu.

- tha, 200 125 200 130 200 130 100 280 +Methanol 50 30 50 40 45 35 35 45 Correspondingsolvent:

+Benzol and methyl acetate a. 30 40 30 10 25 15 +Benzol and methano] 60 40 55 40 55 40 35 50 +Petro1eum naphthe and methyl acetate 60 35 6O 35 55 40 32 l.

KETONIC SOLVENTS TESTED Raw alkali treated acetone Composition of sol- Lmw vent mixture used Samp.1 San1p.2 5amp.8 sol Acein each test tone Alk. Non. Alk. Neu. Alk. Neu.

Single kotonic solvents. 90 50 60 i 70 55 45 30 Binary mixtures 01 1 allege kpttlllmie s01- ven s W1 Benzol 7o 45 e0 45 55 45 0 6 Petroleumnaphtllila" 200 125 200 130 200 130 100 2N1 Anh drous met ay mi 50 30 so 40 4B 35 35 4o Ternary mixtures of above ketonlc solvents and two I othei: solylenltsz v 10!] ,0 'llle 8138' Late an 20 40 3c- ;10 2s 15 Benzol-anh drous methanol? 60 40 55 40 55 40 35 50 Petroleum naphthnmethyl acetate. 60 35 60' 35 55 40 3.

Samples 1, 2 and 3, mentioned in table above were made from acetone usingdilferent catalysts for reaction. One thousand cc. of acetone was used in each case and reaction was catalyzed in Sample 1 with one gram of potassium hydroxide; in Sample 2 with one gram of quick lime (calcium oxide) and especial value, the alkaline product giving in all cases a much slower rate of attack.

Having described the general properties and preparation of ketone condensation solvents, which are the main features of the present invention, I will proceed now to give examples of various paint and varnish removers made with the above materials. It is understood that all formulas given below should be regarded only as examples and that I do not wish to restrict myself to the exact proportions given in these formulas. All these examples will preferably include in the formulas paraffin wax as an agent to retard evaporation of the solvents and in some cases will alsoincludenitrocellulose (scrap celluloid) as an agent to increase the consistency of the paint and varnish remover. It should be noted in this connection that the addition of various solids which are capable of dissolving in one of the solvents used in paint and varnish remover will result in cutting down of the speed of a given solvent or of a mixture of this solvent and other ingredi- Pure acetone 80 seconds Acetone containing 1% of nitro- I cellulose 130 seconds 76% retardation Lngosol 45 seconds Lugosol 1% of nitrocellulose seconds 55% retardation It was also observed that when lugosol was used insolvent mixtures containing dissolved solids, such as wax, or nitrocellulose it produced a substantial. decrease in the undesirable retardation of the efiiciency of a remover, due to the presence of those solids. Retarding action of parafiin wax and of nitrocellulose second cotton) upon the efficiency of various solvents in their mixtures with benzol was determined in the following way:

Various mixtures of benzol with other solvents containing various amounts of parafiin wax in one case, and various amounts of nitrocellulose in the other case were prepared. Approximately an equal amount of each mixture was placed into a test tube and its efliciency was then tested on painted wooden strips, according to the procedure already described. Time of blistering was noted and retardation of the action was calculated in per cent of the action of corresponding solvent mixture without any dissolved solid (as given in Table Results, plated in the form of curves showedthat in the case of parafin wax (curves 1) lugosol-containing mixture had the smallest degree of undesirable drop in efiiciency or rapidity of action. In the case of nitrocellulose (curves 2) lugosol-containing mixture was superior to acetone.

Ihis property of lugosol is of undoubtful value for practical application.

All removers made according to the formulas of the examples below were tested on the same kind of painted surface in order to obtain the comparative figures. For this purpose a part of an old automobile (finished with an oil paint) was secured. Each remover was placed on that surface in approximately the same quantity and the time was noted by means of a stop watch when the blistering or wrinkling of the surface was plainly observable. The cutting power will be expressed in the number of seconds which elapsed before the appearance of such wrinkling. Proportion of ingredients is given by volumes including wax, amount of which corresponds to a wax in melted state.

' Ewamplc 1 Benzol 40 parts by vol.

Anhydrous methyl alcohol- 30 parts by vol. Crude lugosol 30 parts by vol. Paraflin wax 2 parts by vol. Cutting rate 145 seconds.

This remover has a satisfactory consistency and a satisfactory slow rate of evaporation. On standing in open air at room temperature for twenty-four hours the loss in weight was slightly over 3%.

For corresponding paint and varnish removers containing other ketone solvents the rate of cutting was in all cases slower than for the above remover containing crude lugosol, 1. e.:

Acetone 30 parts by vol. Petroleum naphtha 40 parts by vol. Isopropyl alcohol 30 parts by vol. Parafiin wax 2 parts by vol.

Cutting rate 547 seconds.

Petroleum naphtha 30 parts by vol. Isopropyl alcohol 30 parts by vol. Methyl ethyl ketone 40 parts by vol. Paraffin Wax 2 parts by vol.

Cutting rate 720 seconds.

Cutting rate 1500 seconds.

Loss in weight in 24 ho 64 per cent.

Ewample 3 Easample 7' Monochlorbenzol v 50 parts by vol. ilt-later3133:3333: 33 533213? 331i: gnhydgous m 33 g ,3 5 Methyl acetate 30 parts by Pittman-33:13:31: 3 325a b; $31: g zg f g g partsoy Cutting speed 120 seconds. I u mg m e Secon Loss inweightin24 hours 2. 9 per cent.

Example 4 For corresponding acetone remover, i. e. II Monocblorbenzol 50 parts by vol. fi l l iii-f l- 4 Parts y V Iinhydrous methanol 25 parts Ey vol. II y I' II me y a cetone 25 arts vo cohol 30 parts by vol. Paraffin wax 3 garts by vol. Crude lugosol 15 parts by .vol. Cutting speed -l--- 125 seconds. 15 Celluloid scrap 3 parts by weight. Loss in weight in 24 hours- 51. 0 per cent.

Paraffin wax 7 parts by vol.

Guttinurate 105 Seconds Examples 6 and 7 illustrate another ad- I vantage of lugosol against acetone which For corresponding acetone containing rem be Very fi t f m some n f t" 2o mover i. e: ilar to compositions or these examples. lhis advantage consists in reducing the rate of Benzol 45 parts by evaporation or paint and varnish removers, Anhydrous methyl al- 1. e in reducing the speed of evaporation, cohol 301731.;s by VOL which in consequence results in the reduction 25 Acetone 15 parts by VOL of an amount ot a remover necessary to clean Celluloid Scrap 3 parts by wdght. a given area of a painted surftace. The ability Wax 7 parts by VOL of a iemover 1to remain iygt to; a long thine in prac ce 1s a ways .consi ere as an a van- Cuttmg rate Seconds' tage. I have observed that rate of evapora- E Z 5 tion of paint and varnish removers depends mam? e largely not only upon relative amount of Benzol 40 artsb V01 material capable to arrest evaporation, such Anhydrirs'aaaraaar 25 time b? v01: also large PO11 Crude In 0801 r. 15 arts b v01 boiling point and vapor pressureot Wax solv- M h 1 g t 15 p outs included in a remover. With all other ace ate ingredients the same,--higher is the boiling n V0 point of such a solvent, and greater will be uttmg rate! 80 to 90 secon the rate of evaporation of such a remover, therefore the resence amon wax reci For cotresipondmg acetone contmmng itants (non-sol ents) of a subgtance, such is mover lugosol, which will correct this drawback Benzol 40 parts y vol of high boiliiig wax solvents, could be com sidered as a ecided advantage. inhydrous methyl alcohol" Paris a Curves 3 represents graphically rate of 5 g g evaporation of four paint and varnish reg acetate 3 movers mentioned in Examples 6 and 7 and y illustrated in above statement. Cutting rate 100-110 seconds The rate of evaporation was determined by placing approximately equal amount (20 Ewample 6 grams) of each remover into a round tin dish of about 3" in diameter and about y ths of an Trwhlorethylene 40 Parts by inch high. All dishes were then placed in a 30 Parts by special thermostat, heated to a desired tem- Methyl acetate 20 Parts by perature, and loss in weight was determined .g ir "a-""--""- 3 5333i? at regular intervals.

g l ig 'f 1 2 2 p In reviewing the present application it g could be stated that the use of lugosol in paint For crresponding acetone remover, and varnish removers could be considered as q p a useful improvement in the art, because it Triehlorethylene 40 parts by vol, not only introduces a new material into the Acetone 30 parts b ol. paint and varnish remover field but this matee Methyl acetate 20 parts by vol. i'lal will enable those skillful in the art to P ffi wax 2 parts by vol. improve their products. I C tti Speed 120 seconds. I ol m 1. A paint and varnish remover comprisa mixture of 1i uid alkali condensation products of cetone oiling above the boiling point of aceflne.

2. paint and varnish remove-r comprising a mixture of liquid alkali condensation products of acetone having a boiling range between 60 and 170 C.

3. A finish remover containing an alkalipolymerized acetone containing a series of products of which the boiling points range from slightly above that of acetone up to 170 0., together with at least one substance selected from the herein described group consisting of benzol, chlorbenzol, methyl alcohol, ethyl alcohol, isopropyl alcohol, diacetone alcohol, acetone, methyl ethyl ketone, mesityl alcohol, furfural, ethyl acetate, methyl acetate and petroleum naphtha.

4. A finish remover containing an alkalipolymerized acetone containing a series of products of which the boiling points range from slightly above that of acetone up to 170 (1., together with at least one substance se lected from the herein described group consisting of benzol, chlorbenzol, methyl alcohol, ethyl alcohol, isopropyl alcohol, diacetone alcohol, acetone, methyl ethyl ketone, mesityl alcohol, furfural, ethyl acetate, methyl acetate and petroleum naphtha, and a waxy material acting to form an evaporation retarding film on the surface.

5. A finish remover comprising alkali condensation products of acetone and other finish loosening and finish dissolving agents.

6. A finish remover, the rate of evaporation of which is lowered by the presence of liquid alkali condensation products of acetone less volatile than acetone.

7 A paint and varnish remover comprising wax, a wax solvent, methyl acetate 'and products of alkaline condensation of acetone boiling between about 60 and about 170 C.

8. A paint and varnish remover comprising wax, a wax solvent, Lugosol and a cooperating loosening solvent which is a wax precipitant,"such remover having a low rate of evaporation.

9. A composite finish remover comprising as a constituent thereof, mixed condensation products of acetone which condensation products can be fractionated by themselves, to yield fractions about as follows Percent 60 to C a 14 70 to C 26 80 to C 32 to C 8 140 to C 20 10. A finish remover as set forth in claim 9, which also contains a wax and a wax solvent.

In testimony whereof I afiix my signature.

BORIS N. LOUGOVOY. 

